Author: avg Date: Mon Nov 11 19:06:04 2019 New Revision: 354627 URL: https://svnweb.freebsd.org/changeset/base/354627
Log: db_nextframe/i386: reduce the number of special frame types This change removes TRAP_INTERRUPT and TRAP_TIMERINT frame types. Their names are a bit confusing: trap + interrupt, what is that? The TRAP_TIMERINT name is too specific -- can it only be used for timer "trap-interrupts"? What is so special about them? My understanding of the code is that INTERRUPT, TRAP_INTERRUPT and TRAP_TIMERINT differ only in how an offset from callee's frame pointer to a trap frame on the stack is calculated. And that depends on a number of arguments that a special handler passes to a callee (a function with a normal C calling convention). So, this change makes that logic explicit and collapses all interrupt frame types into the INTERRUPT type. Reviewed by: markj Discussed with: kib, jhb MFC after: 3 weeks Differential Revision: https://reviews.freebsd.org/D22303 Modified: head/sys/i386/i386/db_trace.c Modified: head/sys/i386/i386/db_trace.c ============================================================================== --- head/sys/i386/i386/db_trace.c Mon Nov 11 17:45:06 2019 (r354626) +++ head/sys/i386/i386/db_trace.c Mon Nov 11 19:06:04 2019 (r354627) @@ -191,8 +191,6 @@ db_ss(struct db_variable *vp, db_expr_t *valuep, int o #define INTERRUPT 2 #define SYSCALL 3 #define DOUBLE_FAULT 4 -#define TRAP_INTERRUPT 5 -#define TRAP_TIMERINT 6 static void db_nextframe(struct i386_frame **, db_addr_t *, struct thread *); static int db_numargs(struct i386_frame *); @@ -299,6 +297,7 @@ db_nextframe(struct i386_frame **fp, db_addr_t *ip, st { struct trapframe *tf; int frame_type; + int narg; int eip, esp, ebp; db_expr_t offset; c_db_sym_t sym; @@ -317,6 +316,15 @@ db_nextframe(struct i386_frame **fp, db_addr_t *ip, st * actually made the call. */ frame_type = NORMAL; + + /* + * This is the number of arguments that a syscall / trap / interrupt + * service routine passes to its callee. This number is used only for + * special frame types. In most cases there is one argument: the trap + * frame address. + */ + narg = 1; + if (eip >= PMAP_TRM_MIN_ADDRESS) { sym = db_search_symbol(eip - 1 - setidt_disp, DB_STGY_ANY, &offset); @@ -329,20 +337,24 @@ db_nextframe(struct i386_frame **fp, db_addr_t *ip, st strcmp(name, "fork_trampoline") == 0) frame_type = TRAP; else if (strncmp(name, "Xatpic_intr", 11) == 0 || - strncmp(name, "Xapic_isr", 9) == 0) + strncmp(name, "Xapic_isr", 9) == 0) { + /* Additional argument: vector number. */ + narg = 2; frame_type = INTERRUPT; - else if (strcmp(name, "Xlcall_syscall") == 0 || + } else if (strcmp(name, "Xlcall_syscall") == 0 || strcmp(name, "Xint0x80_syscall") == 0) frame_type = SYSCALL; else if (strcmp(name, "dblfault_handler") == 0) frame_type = DOUBLE_FAULT; - /* XXX: These are interrupts with trap frames. */ else if (strcmp(name, "Xtimerint") == 0) - frame_type = TRAP_TIMERINT; + frame_type = INTERRUPT; else if (strcmp(name, "Xcpustop") == 0 || strcmp(name, "Xrendezvous") == 0 || - strcmp(name, "Xipi_intr_bitmap_handler") == 0) - frame_type = TRAP_INTERRUPT; + strcmp(name, "Xipi_intr_bitmap_handler") == 0) { + /* No arguments. */ + narg = 0; + frame_type = INTERRUPT; + } } /* @@ -375,14 +387,11 @@ db_nextframe(struct i386_frame **fp, db_addr_t *ip, st /* * Point to base of trapframe which is just above the - * current frame. + * current frame. Note that struct i386_frame already accounts for one + * argument. */ - if (frame_type == INTERRUPT) - tf = (struct trapframe *)((int)*fp + 16); - else if (frame_type == TRAP_INTERRUPT) - tf = (struct trapframe *)((int)*fp + 8); - else - tf = (struct trapframe *)((int)*fp + 12); + tf = (struct trapframe *)((char *)*fp + sizeof(struct i386_frame) + + 4 * (narg - 1)); esp = get_esp(tf); eip = tf->tf_eip; @@ -395,8 +404,6 @@ db_nextframe(struct i386_frame **fp, db_addr_t *ip, st db_printf("--- syscall"); decode_syscall(tf->tf_eax, td); break; - case TRAP_TIMERINT: - case TRAP_INTERRUPT: case INTERRUPT: db_printf("--- interrupt"); break; @@ -407,8 +414,6 @@ db_nextframe(struct i386_frame **fp, db_addr_t *ip, st switch (frame_type) { case TRAP: - case TRAP_TIMERINT: - case TRAP_INTERRUPT: case INTERRUPT: if ((tf->tf_eflags & PSL_VM) != 0 || (tf->tf_cs & SEL_RPL_MASK) != 0) @@ -418,7 +423,7 @@ db_nextframe(struct i386_frame **fp, db_addr_t *ip, st ebp = 0; break; } - + *ip = (db_addr_t) eip; *fp = (struct i386_frame *) ebp; } _______________________________________________ svn-src-head@freebsd.org mailing list https://lists.freebsd.org/mailman/listinfo/svn-src-head To unsubscribe, send any mail to "svn-src-head-unsubscr...@freebsd.org"
